This invention relates to a trash removal assembly in a fiber processing machine such as a carding machine, a cleaner or the like, particularly for processing cotton fiber. The fiber processing machine is of the type which includes at least two consecutive clothed rolls arranged downstream of a fiber feeding assembly, as viewed in the direction of fiber advance. The clothing may consist of saw teeth, needles or pins. At least one of the clothed rolls is associated with a cutting (severing) edge, for example, of a mote knife, oriented opposite the direction of roll rotation for removing trash or other waste from the fiber material. The mote knife is associated with a waste outlet opening. To expose the fiber material to a draft, the circumferential speed of a downstream arranged a clothed roll is greater than that of an upstream clothed roll. Viewing two consecutive clothed rolls, the downstream clothed roll cooperates with the upstream clothed roll as a takeover and opening roll.
In a known multi-roll cleaner with each clothed roll a mote knife is associated which cooperates with a cover element which shrouds one part of the same roll. The fiber material removed from the upstream roll and entrained by the downstream roll advances in a closed space through the cover in the direction of roll rotation. The cover element extends in a direction against the direction of rotation into the upstream bight, fully occupying that space. Between the mote knife and the open end of the cover element a waste outlet opening for impurities (trash) is provided. Material passing through the waste outlet opening is carried away by a suction stream passing through a hood.
It is an object of the invention to provide an improved waste removal assembly of the above-outlined type in a carding machine, a cleaner or the like.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the fiber processing machine includes a first roll having a circumferential surface carrying a first clothing; a second roll having a circumferential surface carrying a second clothing and adjoining the first roll for taking over fiber material carried by the first roll as the first and second rolls rotate; a nip defined between the first and second clothings at a location where the first and second clothings are closest to one another; a bight defined by a generally triangular area immediately adjoining the nip and bounded by an end thereof and by circumferential length portions of the first and second clothings extending away from the nip end; and a cutting edge positioned in the bight and cooperating with one of the rolls for separating impurities from the fiber material as the fiber material is carried past the cutting edge by the roll clothing.
By virtue of the arrangement of the mote knife according to the invention, a separation of trash or other impurities from the fiber material is possible in the region where fiber opening takes place. By virtue of the fact that the circumferential speed of a consecutive roll is greater than that of a preceding roll, the fiber material is exposed to a draft as it passes from one roll to the other. In such an arrangement all fibers shift relative to one another and thus the fiber is opened. The impurities in the fiber material too, move and reorient themselves in the drafted, and thus loosened, fiber mass. Further, the fiber material, as it passes from one roll to the successive roll, assumes an arcuate course which is opposite to that on the preceding roll. At that location, particularly between the location of separation from the upstream roll and the transfer location on the downstream roll in which the fiber material proceeds freely between the clothing of the two rolls so that it may undergo drafting, the impurities are effectively separated from the fiber material by the mote knife and are guided away from the clothed rolls.